Immunohistochemical detection of tumor cells in the bone marrow of breast cancer patients

BACKGROUND: Contamination of bone marrow and peripheral blood stem cellswith tumor cells is a problem that may be encountered when autologoushematopoietic stem cell transplantation is conducted concurrently withhigh-dose chemotherapy. METHODS: Using monoclonal antibodies to a varietyof tumors, the detection of tumor cells in the bone marrow of breast cancerpatients was studied by immunohistochemistry. RESULTS: KL-1 and CAM5.2 werestrongly reactive with breast cancer cells, but not with normal bone marrowcells. The reactivity of the tumor cells with EMA was not strong, and DF-3and 115D8 yielded only slightly positive reactions. These latter antibodiesalso exhibited some reactivity to normal bone marrow cells. When tumorcells were admixed with normal cells, the sensitivity of CAM5.2 and EMApermitted the detection of one cell in 10(4), but with KL-1, the detectionof one in 10(5) cells was possible. When immunohistochemical staining wasused in testing 40 patients with advanced or recurrent breast cancer,positive reactions were obtained in four of 27 patients (14.8%) with KL-1,four of 26 (15.4%) with CAM5.2, and nine of 37 (23.7%) with KL-1 + CAM5.2,figures similar to those reported by others who studied stage IV patients.CONCLUSIONS: Immunohistochemical staining with KL-1 and CAM5.2 is thereforeconsidered to be a useful technique for detecting contamination by tumorcells.